The present invention relates to a reinforced thermoplastic resin composition and the molded products thereof. More particularly, it relates to a reinforced thermoplastic resin composition which can minimize abrasion of the screws and inner walls of cylinders of the melt kneader and the gate and cavity of the mold in the process of production of the composition and molding, and which causes little warpage of the molded products and also excels in rigidity, strength, self-tapping properties, flame retardancy, etc., and the molded products of the said resin composition.
Amorphous reinforced resins are widely used in the various fields of industry because of their high degree of design freedom and excellent productivity, and many methods for incorporating fibrous inorganic reinforcements, plate-shaped or particulate inorganic fillers or such in the resin compositions for further improvement of strength or rigidity have been proposed. For instance, Japanese Patent Application Laid-Open (KOKAI) No. 6-172611 discloses a glass-reinforced flame-retardant polycarbonate resin composition produced by incorporating a flame retardant and glass fibers, glass flakes or glass beads in a resin composition comprising a polycarbonate resin and an ABS resin. However, the glass fibers, glass flakes and glass beads incorporated in the composition described in the above patent are all high in hardness and therefore cause excessive abrasion of the cylinder inner walls and screws of the extruder or molder and the gate and cavity of the mold in the process of production and molding of the resin compositions, so that it has been difficult to produce with stability a high-quality glass-reinforced flame-retardant polycarbonate resin composition and the molded products of such a resin composition.
Japanese Patent Application Laid-Open (KOKAI) No. 8-127711 discloses a resin composition comprising a polycarbonate resin, an aromatic polyester resin, an elastomeric material, surface-treated talc and/or surface-treated mica, and Japanese Patent Application Laid-Open (KOKAI) No. 8-176339 discloses a resin composition produced by blending talc having a bulk specific gravity of 0.4 to 0.9 in a thermoplastic resin such as polycarbonates. Any of the resin compositions disclosed in these patents is indeed improved in rigidity and warpage in its own way and can lessen abrasion of the screws and cylinders of the melt kneader and molder and the gate and cavity of the mold, but these resin compositions are unsuited for the production of the molded articles which require clamping by self-tapping screws, because these resin compositions can not provide enough self-tapping strength, and thus there were of poor practical applicability.
In Japanese Patent Application Laid-Open (KOKAI) No. 8-073728 discloses a resin composition produced by blending a fibrous inorganic filler such as wollastonite (fibrous calcium silicate) in a polycarbonate resin or a mixture thereof with other thermoplastic resin. Japanese Patent Application Laid-Open (KOKAI) No. 2000-230124 discloses a thermoplastic resin composition comprising a mixture of a thermoplastic resin such as polycarbonates and fibrous β-wollastonite which has been surface-treated with a phosphoric ester compound. Further, Japanese Patent Application Laid-Open (KOKAI) No. 2002-265769 discloses a resin composition obtained by blending wollastonite of a specific particle shape in a resin base comprising a polycarbonate resin or such. The resin compositions disclosed in these patents, however, can provide only those molded products which, although improved in rigidity and self-tapping strength, have high anisotropism and a large warpage because of incorporation of fibrous wollastonite.